苏北海岸带典型盐生植物根际放线菌多样性及其耐盐促生作用研究

发布时间：2018-06-10 01:25

本文选题：盐生植物 + 放线菌　；参考：《江苏师范大学》2017年硕士论文

【摘要】：本研究以江苏省连云港海岸带7种典型盐生植物根际土壤为材料,利用纯培养的方法总共分离得到45株放线菌,并在纯培养分离的基础上,利用免培养技术对盐生植物根际土壤放线菌多样性进行了研究,并对分离的菌株进行16S rRNA基因测序、系统发育分析以及潜在促生活性检测。根据根际放线菌促生潜在性检测,筛选出2株放线菌进行了盆栽实验,研究盐胁迫下根际土壤放线菌对小麦生长的影响。菌株16S rRNA基因测序结果显示,可培养的放线菌分别属于链霉菌属(Streptomyces)、节杆菌属(Arthrobacter)、诺卡氏菌属(Nocardia)、戈登氏菌属(Gordonia)、类诺卡氏菌属(Nocardioides)、微杆菌属(Microbacterium)、分枝杆菌属(Mycobacterium)、壤霉菌属(Agromyces)、微球菌属(Micrococcus)、原小单孢菌属(Promicromonospora)、野野村氏菌属(Nonomuraea)、小单孢菌属(Micromonospora)12个属。通过Miseq PE300平台对7份根际土壤样品中细菌16S rRNA基因的高变异区V5-V7区进行测序,共获得有效序列138541条,共6641个OTU。通过与数据库进行比对分析,7份根际土壤中共探测到66个放线菌属,其中分枝杆菌属(Mycobacterium)、链霉菌(Streptomyces)、小单孢菌属(Micromonospora)和节杆菌属(Arthrabacter)最为丰富。高通量测序结果与我们纯培养分离的结果基本一致,但盐生植物根际土壤中还存在大量未培养的放线菌类群。通过对菌株KLBMP S0027和KLBMP S0039的形态特征观察、生理生化特征、化学分类、16S rRNA与gyrB基因系统发育分析以及DNA-DNA分子杂交的多相分类学研究,证实了2株菌属于诺卡氏菌属的新物种,KLBMP S0027和KLBMP S0039分别命名为江苏诺卡氏菌(Nocardia jiangsuensis sp.nov.),根际栖居诺卡氏菌(Nocardia rhizosphaerihabitans sp.nov.)。对分离得到的放线菌进行解磷、固氮、产吲哚乙酸(IAA)、产1-氨基环丙烷-1-羧酸脱氨酶(ACC脱氨酶)、产铁载体等潜在促生长特性,以及产淀粉酶、木聚糖酶和几丁质酶等酶活性和耐受NaCl能力检测,研究结果发现分离的菌株至少有一种甚至多种促生潜在特征。以菌株KLBMP S0051和KLBMP S0019为材料,通过盐胁迫下接种土壤放线菌对小麦种子萌发及生长的影响初步探究了盐胁迫下两株菌对小麦的促生效应。研究结果发现,盐胁迫下接种菌株KLBMP S0051和KLBMP S0019后分别提高了小麦种子的萌发率1.41和1.98倍,并用KLBMP S0019菌悬液浸种的小麦继续盆栽试验,2%的盐胁迫下发现菌株KLBMP S0019能显著促进小麦植株的生长。本研究对海岸带盐生植物根际土壤的微生物组进行了分析,发现盐生植物根际土壤蕴含着丰富的放线菌资源和促生功能菌株,结合盆栽实验初步探究了盐胁迫下盐生植物根际放线菌对小麦幼苗的促生作用。本研究为后续深入探究盐生植物根际放线菌的生态功能提供了良好的前期基础与材料。
[Abstract]:In this study, 45 strains of actinomycetes were isolated from rhizosphere soil of 7 typical halophytes in Lianyungang coastal zone of Jiangsu Province by pure culture, and on the basis of pure culture, 45 strains of actinomycetes were isolated. The diversity of actinomycetes in the rhizosphere soil of halophytes was studied by using the technique of non-culture, and the 16s rRNA gene sequencing, phylogenetic analysis and potential probiotic activity analysis of the isolated strains were carried out. Based on the potentiality of rhizosphere actinomycetes to promote growth, two strains of actinomycetes were selected for pot experiment to study the effect of rhizosphere soil actinomycetes on wheat growth under salt stress. The results of 16s rRNA gene sequencing showed that, The culturable actinomyces belong to Streptomyces, Arthrobacter, Nocardia, Gordon's, Nocardioideschus, Microbacterium, Mycobacterium, Agromyces, Micrococcus, Promicromonospora, Nocardioideschus, Promonospora, Nocardioidesus, Microbacterium, Mycobacterium, Agromyces, Micrococcus, Promonospora, Promonospora. It belongs to Nonomuraea and Micromonospora (12 genera). The V5-V7 region of 16s rRNA gene in 7 rhizosphere soil samples was sequenced by Miseq PE300 platform. A total of 138541 effective sequences were obtained, with a total of 6641 OTUs. A total of 66 actinomycetes were detected in 7 rhizosphere soil samples by comparing with the database. Mycobacterium, Streptomyces, Micromonospora and Arthrabacter were the most abundant in the genus Mycobacterium, Streptomyces, Micromonospora, and Arthirabacterium, among which Mycobacterium, Streptomyces, Micromonospora and Arthrobacter were the most abundant. The results of high throughput sequencing were consistent with those of our pure culture, but there were still a large number of uncultured actinomycetes in the soil of halophyte rhizosphere. The morphological characteristics, physiological and biochemical characteristics, phylogenetic analysis of 16s rRNA and gyrB gene of KLBMP S0027 and KLBMP S0039, and the multiphase taxonomy of DNA-DNA molecular hybridization were studied. It was confirmed that two new species, KLBMP S0027 and KLBMP S0039, belonging to the genus Nocardia, were named Nocardia jiangsuensis sp. Nov. The potential growth-promoting properties of the isolated actinomycetes, such as phosphorolysis, nitrogen fixation, indole-acetic acid production, 1-aminocyclopropane-1-carboxylic acid deaminase ACC deaminase, iron producing carrier, and amylase production, were studied. The activity of xylanase and chitinase and the ability of tolerance to NaCl were detected. The results showed that the isolated strains had at least one or more potential characteristics of promoting growth. Using KLBMP S0051 and KLBMP S0019 as materials, the effects of soil actinomycetes on wheat seed germination and growth under salt stress were studied. The results showed that inoculation of KLBMP S0051 and KLBMP S0019 under salt stress increased the germination rate of wheat seeds by 1.41 and 1.98 times, respectively. After soaking wheat seeds with bacteria KLBMP S0019, we found that strain KLBMP S0019 could significantly promote the growth of wheat plants under 2% salt stress. In this study, the microflora of halophyte rhizosphere soil in coastal zone was analyzed. It was found that the soil of halophyte rhizosphere contained abundant actinomycetes resources and growth-promoting strains. The effects of rhizosphere actinomycetes of halophytes on wheat seedling growth under salt stress were studied. This study provides a good basis and material for further exploring the ecological function of halophyte rhizosphere actinomycetes.
【学位授予单位】：江苏师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S154.3

【相似文献】